1. Field of the Invention
The present invention relates to a photographing system in which flash photographing is performed in such a manner that a camera and a flash device cooperate with each other, and also relates to a photographic information transmission system in which a first hand-held terminal such as a camera sends a signal relating to photographing to the second hand-held terminal to control a second hand-held terminal such as a flash device.
2. Description of the Related Art
Nowadays, cameras are used in various manners. For example, flash photographing is performed in such a manner that a camera cooperates with an additional device such as a flash device, and photographic data of a camera is sent to a cellular phone. In doing such operations, a photographic information transmission system is used which interconnects a first hand-held terminal such as a camera and a second hand-held terminal such as a flash device.
As an example of such a photographic information transmission system, a photographing system in which a camera and a flash device cooperate with each other to perform flash photographing will be described below.
In this type of photographing system, a common setup is such that a flash device is directly attached to the hot shoe of a camera or that a flash device is connected to the hot shoe of a camera by a cable so that the camera and the flash device are separated from each other by several meters.
In particular, flash photographing with sophisticated lighting is sometimes performed in such a manner that an extension cable is branched so as to connect a plurality of flash devices to a single camera and the flash devices are caused to flash simultaneously with their quantities of flash set independently. In this type of photographing system, it is necessary to use an extension cable having a lot of branches (and subbranches) to connect a plurality of flash devices to a single camera; cumbersome setup work is necessary.
In view of this, recently, a photographing system has been put into practical use in which flash control is performed wirelessly without using any extension cables between a camera and a plurality of flash devices (wireless communication using a flash pulse train is performed).
FIG. 23 to FIG. 25 show an example of such a photographing system, which will be described below.
In this photographing system, flash photographing is performed in the following manner. A master flash device 101 provided between a camera 102 and a plurality of flash devices 103 and 104 generates, as a communication means, a flash pulse train consisting of flash pulses having very small quantities of flash, which is sent from the master flash device 101 to the flash devices 103 and 104.
In this photographing system, preset information is correlated with pulse intervals of a flash pulse train. Information is sent from the camera 102 to the flash devices 103 and 104 being carried by a flash pulse train. In response, the flash devices 103 and 104 emit preliminary flashes and main flashes.
The preliminary flashing and the main flashing will be described below.
(1) Preliminary Flashing
The preliminary flashing will be described with reference to FIG. 24.
FIG. 24 shows a relationship between flash pulse trains generated by the master flash device and preliminary flashes emitted by the flash devices 103 and 104. Specifically, FIG. 24(a) shows flash pulse trains generated by the master flash device 101. FIG. 24(b) shows timing with which the master flash device 101 generates flash pulses. FIG. 24(c) shows timing with which the first flash device 103 emits a preliminary flash. FIG. 24(d) shows timing with which the second flash device 104 emits a preliminary flash.
In this photographing system, the master flash device 101 sends an identifying signal of the camera 102 to the first and second flash devices 103 and 104 prior to photographing.
The first and second flash devices 103 and 104 has recognized an identifying signal of the master flash device 101 in advance so as to function in response to the identifying signal sent from the master flash device 101.
In sending an identifying signal of the camera 102 itself to the first and second flash devices 103 and 104, the master flash device 101 selects, as the identifying signal, one of a plurality of channels (i.e., combinations of presence and absence of a flash pulse (for a plurality of expected flash pulses)). The first and second flash devices 103 and 104 have the same selecting function, and the same channel as set in the master flash device 101 is set in the first and second flash devices 103 and 104.
In FIG. 24(a), symbol P1 denotes a flash pulse train of a command of an identifying signal generated by the master flash device 101. An expected cycle t of generation of flash pulses is predetermined. In the pulse train P1, four flash pulses are generated at maximum. The first and second flash pulses are always generated for prevention of a malfunction and recognition of a start of communication. Four master flash devices 101 can be recognized by combinations of presence and absence of the third and fourth flash pulses (in FIG. 24(a), a solid-line flash pulse indicates xe2x80x9conxe2x80x9d and a broken-line flash pulse indicates xe2x80x9conxe2x80x9d or xe2x80x9coffxe2x80x9d). One of the four combinations is selected and determined as an identifying signal of the camera 102.
A pulse train P2 shown in FIG. 24(a) is a flash pulse train to be used for selecting a particular one of a plurality of flash devices (i.e., the first and second flash devices 103 and 104). An identifying signal corresponding to each flash device is selected because a plurality of flash devices may exist. In the pulse train P2 four combinations of flash pulses are possible depending on presence and absence of a flash pulse (for two expected flash pulses) and hence can specify four flash devices. An identifying signal of a flash device is specified to determine one flash device from the four.
Synchronization is established at the first flash pulse of a flash pulse train such as the pulse train P1 or P2 shown in FIG. 24. The first flash device 103, for example, detects presence/absence of a flash pulse in every expected cycle t. When detecting a flash pulse block such as the pulse train P1 or P2 shown in FIG. 24, the first flash device 103 judges whether the master flash device 101 is selected and whether the first flash device 103 itself is selected.
Then, the master flash device 101 sends a command (i.e., a flash pulse train P3 shown in FIG. 24) for causing only the selected first flash device 103 to emit a flash of a small quantity.
Immediately thereafter, the selected first flash device 103 emits a preliminary flash of a predetermined quantity as shown in FIG. 24(c). The preliminary flash is detected by a light-receiving element of the camera 102 via a photographic lens (not shown).
Each of the first and second flash devices 103 and 104 does not respond any more unless its own identifying signal is newly selected. Therefore, in newly sending a pre-flash command to another flash device, the master flash device 101 needs to send pulse trains P4-P6 as shown in FIG. 24(a). In response to the pulse trains P4-P6, the second flash device 104 emits a preliminary flash. The pulse trains P4-P6 correspond to the respective pulse trains P1-P3 for the first flash device 103.
The interval between the pulse trains P1-P6 is set at least two times the duration of each flash pulse.
In this manner, the master flash device 101 sends pre-flash instructions in order to the first and second flash devices 103 and 104 and the first and second flash devices 103 and 104 emit preliminary flashes as shown in FIGS. 24(c) and 24(d).
The camera 102 calculates quantities of flashes to be emitted in main flashing based on quantities of reflected light from an object which is produced by reflecting the preliminary flashes and is detected in the preliminary flashing shown in FIG. 24.
(2) Main Flashing
FIG. 25 shows a relationship between flash pulse trains generated by the master flash device 101 and main flashes emitted by the flash devices 103 and 104. Specifically, FIG. 25(a) shows flash pulse trains generated by the master flash device 101. FIG. 25(b) shows timing with which the master flash device 101 generates flash pulses. FIG. 25(c) shows timing with which the first flash device 103 emits a main flash. FIG. 25(d) shows timing with which the second flash device 104 emits a main flash.
In the main flashing, as shown in FIG. 25(a), the master flash device 101 sends flash pulse trains to the flash devices 103 and 104 as main flash commands.
FIG. 25 shows flash pulse trains for informing each of the flash devices 103 and 104 about a main flash quantity in the same manner as in the preliminary flashing. In this example, to discriminate the flash pulse trains for the main flashing from those for the preliminary flashing, codes are used that do not cause two or more consecutive absences of a flash pulse in each flash pulse train. In this manner, each of the flash devices 103 and 104 is selected and a main flash quantity is specified individually.
At the end of the commands, the master flash device 101 does not generate a flash pulse at two consecutive expected flash time points and then generates one flash pulse at one expected flash time point. Each of the flash devices 103 and 104 recognizes the end of the main flash command when detecting such a sequence of flash pulses.
When recognizing the end of the main flash command, the flash devices 103 and 104 emit main flashes simultaneously at the specified flash quantity after a very short delay time.
In this photographing system, as described above, the master flash device 101 sends an identifying signal of the camera 102 to the first and second flash devices 103 and 104, whereby the first and second flash devices 103 and 104 are prevented from flashing in response to a flash pulse train of the camera (not shown) of another photographing system.
However, in a case where a lot of photographers simultaneously use various photographing systems, in which wireless communications are performed using flash pulse trains, at positions close to each other in occasions such as news reporting, the following problems arise because the camera 102 uses flash pulse trains as a means for communicating pre-flash commands and main flash commands.
Where many photographing systems of the above kind are used, it is not always expected that an identifying signal of the master flash device in the photographing system of another photographer is different from that of the master flash device 101 in the self photographing system. Where the photographers use the same photographing systems, the number of identifying channels to be used for the flash devices 103 and 104 to recognize the master flash device 101 of the photographing system they belong to may be insufficient. In the above conventional example, in the pulse train P1 shown in FIG. 24(a), the number of identifying channels is restricted to four as combinations of presence and absence of a flash pulse (for two expected flash pulses) is four.
Insufficiency in the number of identifying channels may cause a problem that during flash photographing the first and second flash devices 103 and 104 of the photographing system erroneously respond to flash pulse trains generated by the master flash device (not shown) of another photographing system or that the flash devices of another photographing system erroneously respond to flash pulse trains generated by the master flash device 101 of the photographing system.
Increasing the number of flash pulses naturally increases the number of identifying channels of the master flash device. However, this is not preferable because generation of more flash pulses increases the power consumption. The flashing is by nature low in energy conversion efficiency, and repeatedly emitting flashes of very small quantities to send flash pulse trains causes large energy loss, which leads to smaller quantity of a main flash.
In addition, at the time of sending flash pulses in a main flashing procedure, the flash pulses are sent without interruption as described above because of the restriction on the number of flash pulses, which causes some difficulties in the signal transmission using flash pulses.
The present invention has been made in view of the above circumstances in the art. An object of the invention is therefore to provide a photographing system which enables flash photographing without causing a malfunction due to interference even when many photographers concurrently perform flash photographing at positions close to one another in cases such as news reporting, and which can increase the quantity of a main flash.
Another object of the invention is to provide a photographic information transmission system which enables first and second hand-held terminals to identify the photographic group they belong to without causing a malfunction due to interference.
In the photographing system of the invention in which a flash device is controlled by a signal that is transmitted from a camera to the flash device through a radio communication, a unique identification code for identification of the camera or the flash device is provided in at least one of the camera and the flash device; and the flash device comprises a collating section for collating a unique identification code that is transmitted from the camera by using radio waves as a medium, with a unique identification code originally provided in the flash device.
In this photographing system, the camera that constitutes the photographing system transmits the unique identification code of at least one of the camera and the flash device to the flash device by using radio waves as a medium. In the flash device, the collating section collates the unique identification code that is transmitted from the camera by using radio waves as a medium, with the unique identification code originally provided in the flash device.
There are three collation modes (A), (B), and (C) as follows:
(A) A case that unique identification codes are provided in the camera and the flash device, respectively:
In the flash device, the collating section collates the unique identification codes of the camera and the flash device that are transmitted from the camera by using radio waves as a medium with the unique identification codes of the camera and the flash device originally provided in the flash device.
(B) A case that a unique identification code is provided only in the camera and the flash device is equipped with a memory:
The unique identification code of the camera is transmitted to the memory of the flash device via a connecting cord, for example, and stored in the memory of the flash device. The unique identification code of the camera is transmitted from the camera to the flash device by using radio waves as a medium. In the flash device, the collating section collates the transmitted unique identification code of the camera with the stored unique identification code of the camera.
(C) A case that the camera is equipped with a memory and a unique identification code is provided only in the flash device:
The unique identification code of the flash device is transmitted to the memory of the camera via a connecting cord, for example, and stored in the memory of the camera. The unique identification code of the flash device stored in the camera is transmitted from the camera to the flash device by using radio waves as a medium. In the flash device, the collating section collates the transmitted unique identification code of the flash device with the unique identification code of the flash device provided therein.
This photographing system provides the following advantages.
First, the unique identification code for identification of the camera or the flash device is provided in at least one of the camera and the flash device. And the flash device has the collating section for collating an identification code transmitted by a radio communication with a unique identification code originally provided therein. Therefore, even where many photographing systems are used at positions close to each other, the flash device of the invention identifies the photographing system it belongs to, which can prevents erroneous flashing or erroneous responding to control signals sent from cameras of other photographing systems.
Second, the camera communicates signals for preparation for flashing to the flash device using radio waves rather than sends such signals by wireless communications using flash pulses as in the conventional case. Therefore, it is not necessary to spend, for preparation, part of the energy to be used for flashing of the flash device.
This consequently reduce the power consumption of the flash device. In addition the flash device can emit a flash having a nominal quantity that is indicated by a guide number irrespective of whether radio communications have been performed or not, and the quantity of a main flash can increase. Further, since it is not necessary to spend part of the energy to be used for flashing of the flash device by virtue of radio communications, a limitless number of photographing systems can be provided in each of which an arbitrary camera is correlated with arbitrary flash devices.
Third, it is possible to provide a large number of photographing systems in each of which an arbitrary camera is correlated with arbitrary flash devices so that the invention can accommodate even new models to be developed in the future.
Fourth, the camera""s direct communication with the flash device by radio waves eliminates the necessity of equipping the camera with the conventional master flash device using flash pulses for communication.
In the above photographing system, it is desirable that the camera and the flash device be connected to each other in advance to transmit the unique identification code provided in at least one of the camera and the flash device to the other of the camera and the flash device.
Connecting the camera and the flashing device in advance enables transmission of the unique identification code provided in at least one of the camera and the flash device to the other of the camera and the flash device. This makes it possible to provide various photographing systems in each of which an arbitrary camera is correlated with an arbitrary flash device.
Therefore, according to this photographing system, a free combination of an arbitrary camera and an arbitrary flash device is possible, instead of a fixed combination of a particular camera and a particular flash device. This photographing system is particularly convenient in adding a flash device to a specific camera.
It is desirable that the flash device be provided with a unique identification code; that the camera and the flash device be connected to each other in advance to transmit the unique identification code of the flash device from the flash device to the camera, and in controlling the flash device the camera send the unique identification code of the flash device to the flash device by using radio waves as a medium; and that the collating section collate the unique identification code of the flash device that is transmitted from the camera by using radio waves as a medium with the unique identification code of the flash device that is provided in the flash device.
In this photographing system, the flash device recognizes that the signal has been sent from the camera of the photographing system to which the flash device belongs, by the collating section collating the unique identification code of the flash device transmitted from the camera by using radio waves as a medium with the unique identification code of the flash device that is provided in the flash device.
Therefore, according to this photographing system, the flash device can recognize receipt of the signal from the camera of the photographing system to which the flash device belongs only by collating the unique identification code of the flash device that is transmitted from the camera by a radio communication with the unique identification code of the flash device that is provided in the flash device. The elimination of collation on a unique identification code of the camera provides advantages of decreasing a length of time necessary for preparation for flashing of the flash device and improving responsibility.
It is desirable that the camera of this photographing system store unique identification codes of a plurality of flash devices. This allow the camera of this photographing system to control the plurality of flash devices using their unique identification codes. Therefore, the camera can control the plurality of flash devices.
It is desirable that the photographing system comprise a plurality of flash devices, and that the unique identification code of the camera be transmitted from the camera to each of the plurality of flash devices and stored therein independently.
This allows the camera to control the plurality of flash devices independently using the unique identification code of the camera. Therefore, according to this photographing system, the camera can control the plurality of flash devices.
The invention also provides a photographic information transmission system in which a second hand-held terminal is controlled based on a signal relating to photographing that is transmitted from a first hand-held terminal to the second hand-held terminal by radio transmission, wherein a unique identification code for identification of the first hand-held terminal or the second hand-held terminal is provided in at least one of the first hand-held terminal and the second hand-held terminal; and wherein the second hand-held terminal comprises a collating section for collating a unique identification code that is transmitted from the first hand-held terminal by using radio waves as a medium with a unique identification code originally provided in the second hand-held terminal.
In this photographic information transmission system, the identification code of at least one of the first hand-held terminal and the second hand-held terminal is transmitted from the first hand-held terminal that constitutes the photographic information transmission system to the second hand-held terminal by using radio waves as a medium. In the second hand-held terminal, the collating section collates the unique identification code that is transmitted from the first hand-held terminal by using radio waves as a medium with the unique identification code originally provided in the second hand-held terminal.
There are three collation modes (A), (B), and (C), which are the same as in the above-described photographing system according to the invention and hence will not be described.
This photographic information transmission system provides the following advantages.
First, employing the radio technique using radio waves for transmitting coded data of an identifier can increase the data amount of the identifier and realize reliable transmission at a high transmission rate.
Second, the second hand-held terminal has the collating section for collating an identification code transmitted by radio waves with a unique identification code originally provided therein. Therefore, even where many photographic information transmission systems are used at positions close to each other, the second hand-held terminal identifies the photographic information transmission system it belongs to, which prevents erroneous responding to control signals sent from the first hand-held terminals of other photographic information transmission systems.
In the above photographic information transmission system, it is desirable that the first hand-held terminal and the second hand-held terminal be connected to each other in advance to transmit the unique identification code provided in at least one of the first hand-held terminal and the second hand-held terminal to the other of the first hand-held terminal and the second hand-held terminal.
In this photographic information transmission system, the unique identification code provided in at least one of the first hand-held terminal and the second hand-held terminal is transmitted to the other of the first hand-held terminal and the second hand-held terminal by connecting the first hand-held terminal and the second hand-held terminal. This makes it possible to provide various photographic information transmission systems in each of which an arbitrary first hand-held terminal is correlated with an arbitrary second hand-held terminal.
Therefore, according to this photographing information transmission system, a free combination of two arbitrary hand-held terminals is possible, instead of a fixed combination of two particular hand-held terminals. This photographing system is particularly convenient in adding a hand-held terminal.
It is desirable that the second hand-held terminal be provided with a unique identification code; that the unique identification code of the second hand-held terminal be transmitted from the second hand-held terminal to the first hand-held terminal in advance by connecting the first hand-held terminal and the second hand-held terminal, and in controlling the second hand-held terminal the first hand-held terminal send the unique identification code of the second hand-held terminal to the second hand-held terminal by using radio waves as a medium; and that the collating section collate the unique identification code of the second hand-held terminal that is transmitted from the first hand-held terminal by using radio waves as a medium with the unique identification code of the second hand-held terminal provided in the second hand-held terminal.
In this photographic information transmission system, the collating section of the second hand-held terminal collates the unique identification code of the second hand-held terminal that is transmitted from the first hand-held terminal by using radio waves as a medium with the unique identification code of the second hand-held terminal provided in the second hand-held terminal, whereby the second hand-held terminal recognizes that the signal has been sent from the first hand-held terminal of the photographic information transmission system to which the second hand-held terminal belongs.
Therefore, according to this photographic information transmission system, the second hand-held terminal can recognize arrival of the signal from the first hand-held terminal of the photographic information transmission system to which the second hand-held terminal belongs only by collating the unique identification code of the second hand-held terminal that is transmitted from the first hand-held terminal by radio waves with the unique identification code of the second hand-held terminal provided in the second hand-held terminal itself. This eliminates collation of a unique identification code of the first hand-held terminal, shortens a length of the collation time, and improves the responsibility of the second hand-held terminal accordingly.
It is desirable that the first hand-held terminal and the second hand-held terminal be connected to each other via a lead wire or contact points.
In this photographic information transmission system, the photographer temporarily connects the first hand-held terminal and the second hand-held terminal via a lead wire or contact points to register the unique identification code of the first hand-held terminal or the second hand-held terminal.
Therefore, according to this photographic information transmission system in comparison with Bluetooth in which an identifier is registered by using radio waves, it is possible to reduce possibilities of erroneous connection to an unintended device (hand-held terminal) and to register an identifier in a device to which connection should be made.
It is desirable that unique identification codes of a plurality of second hand-held terminals be transmitted from the plurality of second hand-held terminals to the first hand-held terminal and stored therein. In this photographic information transmission system, the first hand-held terminal controls the plurality of second hand-held terminals using their unique identification codes. Therefore, according to this photographic information transmission system, the first hand-held terminal can control the plurality of the second hand-held terminals.
It is desirable that the photographic information transmission system comprise a plurality of second hand-held terminals, and that the unique identification code of the first hand-held terminal be transmitted from the first hand-held terminal to each of the plurality of second hand-held terminals and stored therein independently. In this photographic information transmission system, the first hand-held terminal controls the plurality of second hand-held terminals independently using the unique identification code of the first hand-held terminal. Therefore, according to this photographic information transmission system, the first hand-held terminal can control the plurality of second hand-held terminals.
It is desirable that the first hand-held terminal be a camera and the second hand-held terminal be a flash device. In this photographic information transmission system, the second hand-held terminal being a flash device is controlled by the first hand-held terminal being a camera with radio waves. Therefore, according to this photographic information transmission system, even where many photographic information transmission systems are used at positions close to each other, the flash device of the invention identifies the photographic information transmission system it belongs to, which prevents erroneous flashing or erroneous responding to a control signals sent from cameras of other photographic information transmission systems.
The camera communicates signals for preparation for flashing to the flash device using radio waves rather than sends such signals by wireless communications using flash pulses as in the conventional case. Therefore, it is not necessary to spend, for preparation, part of the energy to be used for flashing of the flash device.
As a result, the power consumption of the flash device can be reduced and the flash device can emit a flash having a nominal quantity that is indicated by a guide number; the quantity of a main flash can increase. Further, since it is not necessary to spend part of the energy to be used for flashing of the flash device by virtue of radio communications, a limitless number of photographic information transmission systems can be provided, in each of which an arbitrary camera is correlated with arbitrary flash devices.
Further, the camera""s direct control of the flash device with radio waves eliminates the necessity of equipping the camera with a conventional external flash device that uses flash pulses for signal transmission.
It is desirable that the first hand-held terminal be a camera and the second hand-held terminal be a cellular phone. In this photographic information transmission system, the second hand-held terminal being a cellular phone is controlled by the first hand-held terminal being a camera with radio waves. Therefore, according to this photographic information transmission system, photographic data can be transmitted from the camera to the cellular phone.
It is also desirable that the first hand-held terminal be a camera and the second hand-held terminal be a camera. In this photographic information transmission system, the second hand-held terminal being a camera is controlled by the first hand-held terminal being a camera with radio waves. This reduces the time and the amount of operation necessary for determining quality of flash, and also allows simultaneous operations of a plurality of cameras. Accordingly, in this photographic information transmission system, the first hand-held terminal can control a plurality of second hand-held terminals.